Re: [PATCH] ref-filter: initialize empty name or email fields

[Junio C Hamano <gitster@pobox.com>]

Junio C Hamano <gitster@pobox.com> writes:

> Mischa POSLAWSKY <git@shiar.nl> writes:
>
>> Formatting $(taggername) on headerless tags such as v0.99 in Git
>> causes a SIGABRT with error "munmap_chunk(): invalid pointer",
>> because of an oversight in commit f0062d3b74 (ref-filter: free
>> item->value and item->value->s, 2018-10-19).
>>
>> Signed-off-by: Mischa POSLAWSKY <git@shiar.nl>
>> ---
>> If I understand correctly, such tags cannot be produced normally anymore.
>> Therefore I'm unsure how to make tests, and if that is even warranted.
>
> Thanks for spotting.
>
> I am not sure if the approach taken by this patch is the right one,
> though.  I didn't follow the call/dataflow thoroughly, but if we
> replace unfree-able "" with NULL in these places, wouldn't
> fill_missing_values() take care of them?

I think replacing these "" with NULL would be safe, but there are
many places that return xstrdup("") from inside the callees of
populate_value(), so the patch presented here would be more
consistent with the current practice, I think.

So let's take the patch as is, at least for now.  Thanks.

>>  ref-filter.c | 6 +++---
>>  1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/ref-filter.c b/ref-filter.c
>> index f27cfc8c3e..7338cfc671 100644
>> --- a/ref-filter.c
>> +++ b/ref-filter.c
>> @@ -1028,7 +1028,7 @@ static const char *copy_name(const char *buf)
>>  		if (!strncmp(cp, " <", 2))
>>  			return xmemdupz(buf, cp - buf);
>>  	}
>> -	return "";
>> +	return xstrdup("");
>>  }
>>  
>>  static const char *copy_email(const char *buf)
>> @@ -1036,10 +1036,10 @@ static const char *copy_email(const char *buf)
>>  	const char *email = strchr(buf, '<');
>>  	const char *eoemail;
>>  	if (!email)
>> -		return "";
>> +		return xstrdup("");
>>  	eoemail = strchr(email, '>');
>>  	if (!eoemail)
>> -		return "";
>> +		return xstrdup("");
>>  	return xmemdupz(email, eoemail + 1 - email);
>>  }